1. Field of the Invention
The invention provides nucleotide sequences from Cozymeform bacteria which code for the lysR1 gene and a process for the fermentative preparation of amino acids, in particular L-lysine by attenuation of the lysR1 gene. The lysR1 gene codes for the LysR1 protein, which is a transcription regulator of the LysR family.
2. Discussion of the Background
L-amino acids, in particular L-lysine, are used in human medicine and in the pharmaceutical industry, in the foodstuffs industry, and most particularly in animal nutrition.
It is known that amino acids can be produced by fermentation of strains of Coryneform bacteria, in particular Corynebacterium glutamicum. On account of the great importance of these amino acids constant efforts are being made to improve the production processes. Improvements in production processes may involve fermentation technology measures, such as for example stirring and provision of oxygen, or the composition of the nutrient media, such as for example the sugar concentration during the fermentation, or the working up to the product form by for example ion exchange chromatography, or the intrinsic performance properties of the microorganism itself.
Methods involving mutagenesis, selection and mutant selection are used to improve the performance properties of these microorganisms. In this way strains are obtained that are resistant to antimetabolites or are auxotrophic for regulatorily significant metabolites and that produce amino acids.
Methods of recombinant DNA have also been employed for improving strains of Corynebacterium strains which produce L-amino acids.
However, there remains a critical need for improved methods of producing L-amino acids and thus for the provision of strains of bacteria producing higher amounts of L-amino acids. On a commercial or industrial scale even small improvements in the yield of L-amino acids, or the efficiency of their production, are economically significant. Prior to the present invention, it was not recognized that attenuation of lysR1 gene encoding the a LysR1 transcriptional regulation protein would improve L-amino acid yields.